An electron heating mechanism in the outflow region from the X‐type neutral line
An electron heating mechanism in the outflow region from the X‐type neutral line
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DOI：
10.1029/2002ja009810
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发表时间：
2003-09
影响因子：
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通讯作者：
K. Fujimoto;S. Machida
中科院分区：
文献类型：
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作者：
K. Fujimoto;S. Machida
通过线性分析和2 1/2维全粒子模拟，研究了强霍尔电流对电子加热的机理。强霍尔电流是由磁重联过程中扩散区内流出区电子和离子之间的大速度差引起的。动力学色散关系的数值解表明，未来不稳定模式随电子-离子相对速度Vd的变化而变化；当Vd低于电子热速度ve的很大一部分时，主要是动力学跨场流不稳定性（KCSI），而当Vd超过该临界速度时，首先激发电子回旋漂移不稳定性（ECDI）。我们表明，由于KCSI，电子被加热平行于环境磁场，而由于ECDI，电子被加热垂直于环境磁场。特别是，当ECDI占主导地位时，电子被迅速加热到高温。当Vd/ve < 1时，电子加热无效。
[1] A linear analysis and 2 1/2-dimensional full-particle simulations are performed to investigate mechanisms of an electron heating due to a strong Hall current, which is caused by a large velocity difference between electrons and ions in the outflow region inside the diffusion region of the magnetic reconnection process. The numerical solution of the kinetic dispersion relation indicates that the prospective unstable mode varies according to the electron-ion relative velocity Vd; the kinetic cross-field streaming instability (KCSI) is dominant when Vd is under the substantial fraction of the electron thermal velocity ve, while the electron cyclotron drift instability (ECDI) is first excited for the case where Vd exceeds that critical velocity. We show that electrons are heated parallel to the ambient magnetic field due to the KCSI and perpendicularly due to the ECDI. In particular, electrons are very quickly heated up to a high temperature when the ECDI is dominant. However, the electron heating is ineffective when Vd/ve < 1.